U.S. patent number 8,506,222 [Application Number 13/054,783] was granted by the patent office on 2013-08-13 for nut plate assembly and methods of using the same.
This patent grant is currently assigned to Fatigue Technology, Inc.. The grantee listed for this patent is Timothy Howard Johnson, Leonard Frederick Reid, James Ryunoshin Ross. Invention is credited to Timothy Howard Johnson, Leonard Frederick Reid, James Ryunoshin Ross.
United States Patent |
8,506,222 |
Reid , et al. |
August 13, 2013 |
Nut plate assembly and methods of using the same
Abstract
A nut plate assembly includes a nut retainer and a bushing for
expanding a tubular body of the retainer. The retainer assembly is
used to cold work an opening of a workpiece in order to fix the nut
retainer assembly relative to the workpiece. A nut member can be
snapped into the retainer. A method of installation includes
passing a mandrel through the bushing to radially expand the
bushing into a tubular body of the retainer. The tubular body is
compressed between the workpiece and bushing as the bushing is
displaced radially causing corresponding radial displacement of the
tubular body. The expanded bushing applies pressure to the tubular
body for a desired fit between the nut retainer and workpiece.
Inventors: |
Reid; Leonard Frederick
(Renton, WA), Johnson; Timothy Howard (Seattle, WA),
Ross; James Ryunoshin (Seattle, WA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Reid; Leonard Frederick
Johnson; Timothy Howard
Ross; James Ryunoshin |
Renton
Seattle
Seattle |
WA
WA
WA |
US
US
US |
|
|
Assignee: |
Fatigue Technology, Inc.
(Seattle, WA)
|
Family
ID: |
41551037 |
Appl.
No.: |
13/054,783 |
Filed: |
July 17, 2009 |
PCT
Filed: |
July 17, 2009 |
PCT No.: |
PCT/US2009/051065 |
371(c)(1),(2),(4) Date: |
April 13, 2011 |
PCT
Pub. No.: |
WO2010/009442 |
PCT
Pub. Date: |
January 21, 2010 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20110182692 A1 |
Jul 28, 2011 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61082098 |
Jul 18, 2008 |
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Current U.S.
Class: |
411/111; 411/432;
411/501; 411/112; 411/108; 411/119; 411/183; 411/204 |
Current CPC
Class: |
F16B
37/044 (20130101); B23P 9/025 (20130101); F16B
37/062 (20130101); Y10T 29/4994 (20150115) |
Current International
Class: |
F16B
39/284 (20060101) |
Field of
Search: |
;411/108,111,112,119,174,176,183,204,321,323,431,432,501,571,918
;16/2.1,2.4 |
References Cited
[Referenced By]
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Other References
US. Appl. No. 09/603,857, filed Jun. 26, 2000, Skinner et al. cited
by applicant .
Merriam Webster's Collegiate Dictionary, Tenth Edition, 1997, p.
154. (1). cited by applicant.
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Primary Examiner: Delisle; Roberta
Attorney, Agent or Firm: Seed IP Law Group PLLC
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit under 35 U.S.C. .sctn.119(e) of
U.S. Provisional Patent Application No. 61/082,098 filed Jul. 18,
2008. This provisional application is incorporated herein by
reference in its entirety.
Claims
What is claimed is:
1. An assembly for retaining a nut member, the assembly comprising:
a nut retainer including a nut retaining section and an expandable
tubular body connected to the nut retaining section, the nut
retaining section including an abutment portion configured to
contact a workpiece when the expandable tubular body is positioned
in an opening of the workpiece, the expandable tubular body
including a tubular body inner surface surrounding a tubular body
passageway and defining a tubular body inner perimeter; and a
bushing including a bushing outer surface defining a first outer
perimeter and a bushing inner surface at least partially
surrounding a bushing passageway, the first outer perimeter
substantially equal to or smaller than the tubular body inner
perimeter, the bushing passageway adapted to receive a mandrel
capable of radially expanding the bushing and the tubular body when
the tubular body circumferentially surrounds the bushing so as to
form a first interference fit between the tubular body and the
workpiece and a second interference fit between the bushing outer
surface and the tubular body inner surface.
2. The assembly of claim 1, further comprising: a nut member
configured and dimensioned to couple to the nut retaining section,
the nut member being adapted to receive and retain another
component.
3. The assembly of claim 2, wherein the nut member is axially and
rotationally fixable to the nut retaining section.
4. The assembly of claim 1, wherein the bushing has a longitudinal
length that is substantially equal to a longitudinal length of the
tubular body.
5. The assembly of claim 1, wherein the bushing comprises a first
section and a second section that cooperate to define the bushing
passageway, the first section includes the first outer perimeter,
the second section includes a second outer perimeter that is larger
than the first outer perimeter, the second outer perimeter and an
outer perimeter of the tubular body form an outer surface for
expanding substantially the entire opening when the first section
is within the tubular body.
6. The assembly of claim 1, wherein the bushing has a first
section, a second section adapted to expand a portion of the
opening of the workpiece, and a shoulder between the first section
and the second section, the shoulder is configured to contact an
end of the tubular body when the first section is positioned along
the tubular body passageway.
7. The assembly of claim 6, wherein at least a portion of an outer
surface of the second section has a transverse profile that is
substantially geometrically congruent to a transverse profile of at
least a portion of a body outer surface of the tubular body.
8. An installation comprising: a workpiece including a first side,
a second side, and an opening extending between the first side and
the second side, the opening having a longitudinal length; and a
retainer assembly comprising a tubular section having been expanded
to provide radial expansion along at least most of the longitudinal
length of the opening of the workpiece, the retainer assembly
further comprising a nut, a retainer including a nut retaining
section and an expanded tubular body, the nut retaining section
adapted to receive and retain the nut and to physically contact the
first side of the workpeice, the expanded tubular body extending
through at least a portion of the opening and having a passageway,
and an expanded bushing extending through the passageway of the
tubular body and having a bushing passageway, wherein the tubular
section of the retainer assembly includes the tubular body of the
retainer and the bushing.
9. The installation of claim 8, wherein the bushing has a
longitudinal length that is substantially equal to or larger than
the longitudinal length of the opening of the workpiece.
10. The installation of claim 8, wherein the bushing includes a
first section and a second section that cooperate to define the
bushing passageway, the first section extends through the
passageway of the tubular body, the second section is adjacent to
the tubular body and protrudes radially outward beyond an inner
surface of the expanded tubular body, a first interference fit is
between the first section and the inner surface of the tubular
body, and a second interference fit is between the second section
and the workpiece.
11. The installation of claim 8, wherein the bushing has a first
section and second section, the first section is surrounded by the
expanded tubular body, the second section protrudes from the
tubular body and through a portion of the opening located between
the tubular body and the second side of the workpiece.
12. The installation of claim 11, wherein both an outer surface of
the tubular body and an outer surface of the second section have
been radially expanded to provide substantially uniform radial
expansion throughout at least most of the longitudinal length of
the opening.
13. The installation of claim 11, wherein the second section of the
bushing has an outer surface that is substantially geometrically
congruent to an outer surface of the tubular body.
14. The installation of claim 8, further comprising: a first
interference fit between an outer surface of the tubular body and
an inner surface of the workpiece, the inner surface of the
workpiece defining the opening; and a second interference fit
between an inner surface of the tubular body and an outer surface
of the expanded bushing.
15. The installation of claim 8, wherein the opening has been
radially displaced along substantially all of the longitudinal
length of the opening because of sufficient radial displacement
along substantially all of a longitudinal length of the
bushing.
16. A method of installation comprising: positioning a tubular body
of a nut retainer in an opening of a workpiece such that a nut
retaining section of the nut retainer is on a first side of the
workpiece and the tubular body extends away from the nut retaining
section towards a second side of the workpiece opposing the first
side, the nut retaining section is being adapted to receive and
hold a nut member; positioning a bushing in a passageway of the
tubular body of the nut retainer; and expanding the bushing using a
mandrel to cause radial expansion of both the tubular body and a
surface of the workpiece that defines the opening.
17. The method of claim 16, further comprising: coupling a nut
member to the nut retaining section after expanding the
bushing.
18. The method of claim 16, wherein expanding the bushing further
comprises: expanding a first section of the bushing to cause
expansion of both the tubular body surrounding the first section
and a first portion of the opening; and expanding a second section
of the bushing to cause expansion of a second portion of the
opening, the second portion of the opening separates the tubular
body and the second side of the workpiece.
19. The method of claim 16, wherein expanding the bushing further
comprises: forming a first interference fit between an outer
surface of the tubular body and an inner surface of the workpiece,
the inner surface of the workpiece defining the opening; and
forming a second interference fit between an inner surface of the
tubular body and a first outer surface of the bushing.
20. The method of claim 19, further comprising: forming a third
interference fit between a second outer surface of the bushing and
the inner surface of the workpiece.
Description
BACKGROUND
1. Technical Field
This disclosure generally relates to nut plate assemblies and
methods of using the same.
2. Description of the Related Art
Rivetless nut plates are often installed into structural workpieces
in order to couple components to the workpieces. Conventional nut
plates may include a bracket and a nut coupleable to the bracket.
The nut can receive an externally threaded component (e.g., a bolt
or a screw) after the bracket has been secured to the workpiece.
When the installed nut plate supports an attached component, a flat
face of the bracket can bear against the workpiece to help
distribute loads to the workpiece to prevent excessive stresses in
the workpiece.
One type of conventional bracket for a nut plate has an expandable
one-piece sleeve that a user can insert into an opening of the
workpiece. The sleeve is then displaced radially against a tubular
surface of the workpiece that defines the workpiece opening.
Unfortunately, the one-piece sleeve has a fixed longitudinal length
rendering the bracket unsuitable for installation in workpiece
openings having longitudinal lengths that are significantly
different from the length of the sleeve. A large variety of
brackets having sleeves of different dimensions must therefore be
kept in stock to install nut plates in different sized
openings.
Conventional installation techniques involve expanding the sleeves
by swaging the sleeve into the workpiece such that the bracket is
fixedly coupled to the structural workpiece. For example, a mandrel
moving through a passageway of the sleeve can expand the sleeve to
create an interference fit between the sleeve and the workpiece.
The installed nut plate bracket resists torques and axial
push/pull-out. In addition, the expansion of the sleeve may induce
compressive residual stresses into the workpiece material
surrounding the opening. If the sleeve extends through a portion of
the opening, compressive stresses may be induced only along that
portion of the opening. Thus, residual stress may not be induced
throughout the length of the opening resulting in a workpiece that
is susceptible to fatigue failures.
BRIEF SUMMARY OF THE DISCLOSURE
Some embodiments disclosed herein include a nut plate assembly for
connecting two or more components. The installed nut plate assembly
resists a wide range of static loads, dynamic loads, and
combinations thereof. The nut plate assembly includes a retainer
assembly with a tubular section, which includes an expandable
member and an outer tubular body that surrounds the expandable
member. The expandable member and outer tubular body cooperate to
achieve a desired fit with the workpiece.
In some embodiments, the nut plate assembly includes an expandable
member and a nut retainer. The expandable member and a tubular body
of the nut retainer cooperate to fixedly couple the nut retainer to
a workpiece. The nut retainer retains a nut member that provides
threads for receiving an externally threaded portion of another
component. Loads can be applied to the nut retainer via the nut
member while the nut retainer minimizes, limits, or substantially
eliminates unwanted damage to the component. In some embodiments,
the expandable member extends through the tubular body and is used
to radially-expand the tubular body to provide a desired grip
length based on a thickness of the workpiece.
The tubular body of the nut retainer and the expandable member are
radially expanded together. For example, the expandable member in
the form of a bushing can be radially expanded by a mandrel to
radially expand the tubular body of the nut retainer and the
workpiece. The radially-expanded expandable member, in some
embodiments, achieves high levels of expansion in the tubular body
of the retainer, which in turn causes expansion of the workpiece to
improve fatigue performance of the workpiece.
In some embodiments, an assembly for retaining a nut member
comprises a nut retainer and a bushing. The nut retainer includes a
nut retaining section and an expandable tubular body connected to
the nut retaining section. The nut retaining section includes an
abutment portion configured to contact a workpiece when the
expandable tubular body is positioned in an opening of the
workpiece. The expandable tubular body includes a body inner
surface that surrounds a tubular body passageway and that defines a
tubular body inner perimeter. The bushing includes a bushing outer
surface defining a first outer perimeter and a bushing inner
surface at least partially surrounding a bushing passageway. The
first outer perimeter of the bushing is substantially equal to or
smaller than the body inner perimeter. The bushing passageway is
adapted to receive a mandrel capable of radially expanding the
bushing and the tubular body when the tubular body
circumferentially surrounds the bushing so as to produce an
interference fit between the tubular body and the workpiece and an
interference fit between the bushing outer surface and the body
inner surface.
In some embodiments, an installation comprises a workpiece and a
retainer. The workpiece includes a first side, a second side, and
an opening extending between the first side and the second side.
The opening has a longitudinal length. The retainer assembly
includes a tubular section that has been expanded to provide radial
expansion along at least most of the longitudinal length of the
opening of the workpiece. In some embodiments, at least 50% of the
longitudinal length of the opening of the workpiece is expanded. In
some embodiments, at least 75% of the longitudinal length of the
opening of the workpiece is expanded to significantly increase
fatigue performance of the workpiece. In some embodiments, at least
90% of the longitudinal length of the opening of the workpiece is
expanded to significantly increase fatigue performance of material
of the workpiece proximate to the first and second side.
The retainer assembly, in some embodiments, includes a nut and a
retainer including a nut retaining section and an expanded tubular
body. The nut retaining section is adapted to receive and retain
the nut and to physically contact the first side of the workpeice.
The expanded tubular body extends through at least a portion of the
opening and has a passageway. The retainer assembly further
includes an expanded bushing that extends through the passageway of
the tubular body and has a bushing passageway. The tubular section
of the retainer assembly includes the tubular body of the retainer
and the bushing.
In some embodiments, a method of installation includes positioning
a tubular body of a nut retainer in an opening of a workpiece such
that a nut retaining section of the retainer is on a first side of
the workpiece and the tubular body extends away from the nut
retaining section towards a second side of the workpiece opposing
the first side. The nut retaining section is adapted to receive and
hold a nut member. A bushing is positioned in a passageway of the
tubular body of the nut retainer. The bushing is expanded using a
mandrel to cause radial expansion of both the tubular body and a
surface of the workpiece that defines the opening.
In yet other embodiments, a method of installation includes
positioning a nut retainer in an opening of the workpiece. A
portion of the retainer is on one side of the workpiece and another
portion of the retainer is on the other side of the workpiece
and/or within the opening. At least a portion of the nut retainer
can receive and hold a nut member. A bushing is positioned in a
passageway of the nut retainer. The bushing can be expanded using
the mandrel so as to cause real expansion of both the tubular body
and a surface of the workpiece that defines the opening.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
In the drawings, identical reference numbers identify similar
elements or acts. The sizes and relative positions of elements in
the drawings are not necessarily drawn to scale.
FIG. 1 is a side elevational view of a nut plate assembly installed
in a workpiece, according to one illustrated embodiment.
FIG. 2 is a cross-sectional view of the nut plate assembly and
workpiece of FIG. 1.
FIG. 3 is an isometric view of a nut retainer of a nut plate
assembly, according to one illustrated embodiment.
FIG. 4 is a side elevational view of the nut retainer of FIG. 3,
according to one illustrated embodiment.
FIG. 5 is a top plan view of the nut retainer of FIG. 3, according
to one illustrated embodiment.
FIG. 6 is a bottom view of the nut retainer of FIG. 3, according to
one illustrated embodiment.
FIG. 7 is an isometric view of a nut member of a nut plate
assembly, according to one illustrated embodiment.
FIG. 8 is a side elevational view of the nut member of FIG. 7,
according to one illustrated embodiment.
FIG. 9 is a top plan view of the nut member of FIG. 7, according to
one illustrated embodiment.
FIG. 10 is a perspective view of an expandable member of a nut
plate assembly, according to one illustrated embodiment.
FIG. 11 is a top plan view of the expandable member of FIG. 10.
FIG. 12 is a side elevational view of the expandable member of FIG.
10.
FIG. 13 is a cross-sectional view of the expandable member of FIG.
11 taken along a line 13-13.
FIG. 14 is a side elevational view of an installation system having
an installation tool and an assembled nut plate assembly ready for
installation, according to one illustrated embodiment.
FIG. 15 is a partial cross-sectional view of the installation
system of FIG. 14, wherein the nut plate assembly is positioned on
a mandrel.
FIG. 16 is a partial cross-sectional view of a portion of an
installation system, wherein a mandrel is ready to expand a nut
plate assembly, according to one illustrated embodiment.
FIG. 17 is a partial cross-sectional view of the installation
system of FIG. 16, wherein the mandrel is expanding a multi-piece
tubular section of a retainer assembly, according to one
illustrated embodiment.
FIG. 18 is a cross-sectional view of the post-expanded multi-piece
tubular section of FIG. 17 spaced from the mandrel, according to
one illustrated embodiment.
FIG. 19 is a side elevational view of a nut plate assembly that has
a multi-piece tubular section for expanding an opening of a
workpiece, according to one illustrated embodiment.
FIG. 20 is a cross-sectional view of the nut plate assembly of FIG.
19 in a workpiece, according to one illustrated embodiment.
FIG. 21 is an isometric view of an expandable member, according to
one illustrated embodiment.
FIG. 22 is a side elevational view of the expandable member of FIG.
21.
FIG. 23 is a top plan view of the expandable member of FIG. 21.
FIG. 24 is a side elevational view of a mandrel assembly for
installing a nut plate assembly, according to one illustrated
embodiment.
FIG. 25 is a cross-sectional view of the mandrel assembly of FIG.
24 taken along a line 25-25.
FIG. 26 is a cross-sectional view of the mandrel assembly of FIG.
24 operating to install a nut plate assembly into an opening of a
structural workpiece.
FIG. 27 is a cross-sectional view of the mandrel assembly of FIG.
26 showing an expandable member about to be moved into the radially
expanded tubular body of a nut retainer.
FIGS. 28A-28E are detailed views of one region of various mandrels
carrying expandable members.
DETAILED DESCRIPTION OF THE DISCLOSURE
In the following description, certain specific details are set
forth in order to provide a thorough understanding of various
embodiments of the invention. However, one skilled in the art will
understand that the invention may be practiced without these
details. The assemblies and processes disclosed herein can be used
to couple together a desired number of components. The components
can include, without limitation, workpieces, connectors, mounting
components, and the like. The terms "proximal" and "distal" are
used to describe the illustrated embodiments and are used
consistently with the description of non-limiting exemplary
applications. The terms proximal and distal are used in reference
to the user's body when the user operates an installation system,
unless the context clearly indicates otherwise.
Unless the context requires otherwise, throughout the specification
and claims which follow, the word "comprise" and variations
thereof, such as, "comprises" and "comprising" are to be construed
in an open, inclusive sense, that is as "including, but not limited
to."
As used in this specification and the claims, the singular forms
"a," "an," and "the" include plural referents unless the content
clearly dictates otherwise. Thus, for example, reference to a nut
plate assembly that includes "a bushing" includes a nut plate
assembly with a single bushing or nut plate assembly with two or
more bushings, or both. It should also be noted that the term "or"
is generally employed in its sense including "and/or" unless the
context clearly dictates otherwise.
FIGS. 1 and 2 show a nut plate assembly 100 installed within an
opening 106 of a workpiece 110. The nut plate assembly 100 includes
a nut member 120 and a retainer assembly 121 fixedly coupled to the
workpiece 110. The retainer assembly 121 includes a nut retainer
122 adapted to releasably hold the nut member 120 and an expandable
member 126, illustrated as a bushing.
The illustrated nut plate assembly 100 has a multi-piece tubular
section 130 that includes the bushing 126 and a tubular body 136 of
the nut retainer 122 circumferentially surrounding the bushing 126.
The tubular section 130 has been expanded to fixedly couple the nut
plate assembly 100 to the workpiece 110. A mounting component
(e.g., a screw, bolt, threaded member, and the like) can be
threadably coupled to the nut member 120 such that the mounting
component is coupled to the workpiece 10 by the nut plate assembly
100.
The nut plate assembly 100 can be installed into various types of
workpieces. As used herein, the term "workpiece" is broadly
construed to include, without limitation, a parent structure, such
as a thin sheet of metal, a structural component, etc., having at
least one opening suitable for receiving at least a portion of the
nut plate assembly 100. The opening can be a through-hole (with or
without back side access) or other type of hole. The illustrated
opening 106 of FIG. 2 extends between a first side 138 and a second
side 139 of the workpiece 110. In some embodiments, the workpiece
110 is a structural workpiece, such as a bulkhead, a fuselage, a
tank (e.g., fuel tank), an engine, or other structural component of
an aircraft. If the workpiece 110 is a multi-component structure,
the nut plate assembly 100 can hold the components of the structure
together with a desired clamp-up force. Multi-component structures
include, without limitation, a stack of plates, multi-layer
laminates, and the like. The illustrated structural workpiece 110
of FIGS. 1 and 2 can comprise, without limitation, one or more
metals (e.g., steel, aluminum, titanium, and the like), polymers,
plastics, composites, or other materials suitable for engaging one
or more of the components of the nut plate assembly 100.
FIGS. 3-6 show the nut retainer 122 that includes a nut retaining
section 140 and the tubular body 136. The nut retaining section 140
has a generally U-shaped profile, as illustrated in FIG. 4, and
includes an abutment portion 144 configured to contact the
workpiece 110 when the tubular body 136 is within the workpiece
opening 106, as shown in FIG. 2. The abutment portion 144 can be in
the form of a plate that includes a first face 166 and a second
face 168 opposing the first face 166. The illustrated first face
166 is generally planar to provide a relatively large surface area
for physically contacting the workpiece 110. The first face 166 can
lay generally flat along the workpiece 110.
The illustrated retaining section 140 includes a pair of flexible
retention elements 150, 152 extending away from the abutment
portion 144 and partially surrounding a longitudinal axis 158 of
the tubular body 136. The retention elements 150, 152 include
apertures 160, 162, respectively. The nut member 120 can be
inserted between the retention elements 150, 152 to spread the
retention elements 150, 152 outwardly, as indicated by the arrows
154, 156 of FIG. 4, such that elongated members 170, 172 of the nut
member 120 move into the apertures 160, 162, respectively. FIG. 2
shows the elongate members 170, 172 positioned within the apertures
160, 162, respectively.
Referring again to FIGS. 3-6, the tubular body 136 includes a
tubular body passageway 180, an inner surface 182 surrounding the
passageway 180, and an outer surface 184 opposing the inner surface
182. The inner surface 182 defines an inner perimeter 188, and the
outer surface 184 defines an outer perimeter 190. The outer
perimeter 190 can be sized to closely fit within the opening 106 of
the workpiece 110 before the tubular body 136 is radially expanded.
For example, a clearance fit with a minimal amount of clearance, a
slight clearance fit, or the like can be formed by the outer
surface 184 and the workpiece 110.
The tubular body 136 can have various cross-sectional profiles,
including, without limitation, a circular profile, a polygonal
profile, an elliptical profile, or the like. The tubular body 136
shown in FIG. 6 has an approximately circular profile that is
substantially geometrically congruent to the profile of the opening
106.
Various types of manufacturing processes can be used to make the
nut retainer 122. For example, stamping processes, machining
processes, bending processes, and the like can be employed. In some
embodiments, a flat sheet of metal is cut (e.g., die cut) into a
desired configuration. The cut piece of metal is then stamped to
form the illustrated nut retaining section 140. The nut retaining
section 140 is then coupled to the tubular body 136. The tubular
body 136 can be made of a material, or combination of materials,
that permits radial expansion. The tubular body 136 can experience
plastic deformation to form a permanent interference fit with the
workpiece 110 and elastic deformation to contract onto and form a
permanent interference fit with the bushing 126. The expanded
tubular body 136, in some embodiments, radially contracts (e.g.,
elastically contracts) onto the bushing 126. In some embodiments,
the tubular body 136 experiences only permanent deformation. Such
embodiments are well suited for the simultaneous expansion of the
bushing 126 and the tubular body 136, as discussed in connection
with FIGS. 14-18.
FIGS. 7-9 show the nut member 120 having an inner perimeter 191 and
an outer perimeter 193. In some embodiments, the inner perimeter
191 is at least partially threaded for threadably coupling to
another component. In other embodiments, the inner perimeter 191 is
configured to receive a non-threaded component. The nut member 120
may include one or more fixation elements, such as fasteners, set
screws, and the like, to fixedly retain another component. The nut
member 120 can also include an outer shoulder 199 that can engage a
cap or the like. For example, the outer perimeter 193 can be sized
such that a cap can be inserted over the nut member 120. FIG. 2
shows an inner shoulder 198 of the nut member 120 that can act as
an axial restraint for the mandrel used to install the nut plate
assembly 100.
In some embodiments, including the illustrated embodiment of FIGS.
7-9, the nut member 120 has a base 200 that includes the elongate
members 170, 172, illustrated as generally rectangular tabs. The
shape, size, and number of the elongate members can be selected
based on the desired interaction between the nut member 120 and the
nut retainer 122. When the nut member 120 is coupled to the
retainer 122, the base 200 can be held against the face 168 to
reduce, limit, or substantially eliminate relative movement between
the base 200 and the retainer 122.
The illustrated nut member 120 can be snapped into the retainer 122
of FIGS. 1 and 2 before, after, or during the installation of the
retainer 122. Additionally, the nut member 120 can be removed from
the retainer 122, if needed or desired. The retention elements 150,
152 can be deflected outwardly until the elongate members 170, 172
are released from the retention elements 150, 152. The nut member
120 is then moved away from the retainer 122. Another nut member,
or other type of component, can then be installed in the retainer
122.
Other types of nut members can be utilized with the nut retainer
122. For example, one-piece or multi-piece nut members can be
incorporated into the nut plate assembly 100. U.S. application Ser.
No. 11/445,951, which is incorporated by reference herein in its
entirety, discloses such nut members.
Referring to FIGS. 10-13, the expandable member 126 is in the form
of a bushing. As used herein, the term "expandable member" is a
broad term and includes, but is not limited to, a bushing, a
fastener, a structural expandable member (e.g., an expandable
member that is incorporated into a structural workpiece), or other
structures that are suitable for coupling to a workpiece. The
bushing 126 can be expanded from a first configuration to a second
configuration. In some embodiments, for example, the bushing 126 is
radially expanded from an initial configuration to a second
configuration in order to form an interference fit with a
structural workpiece or a nut retainer, or both, as well as other
components, if needed or desired. The term "expandable member"
refers to a member both in a pre-expanded state and post-expanded
state, unless the context clearly dictates otherwise. Various types
of expansion processes can be employed to expand the expandable
members. In a cold expansion process, for example, the expandable
member is radially expanded without appreciably raising the
temperature of the expandable member to produce residual stresses
in the workpiece to enhance fatigue performance. The residual
stresses are preferably compressive stresses that can minimize,
limit, inhibit, or prevent crack initiation and/or crack
propagation. As noted above, expandable members can be in the form
of bushings. A bushing may be, without limitation, a sleeve
(including a split sleeve), a tubular member (with or without
flanges), and the like. The bushing may have various features, such
as coatings, liners, seating features (e.g., flanges) and the like.
As used herein, the term "expanding" and variations thereof (e.g.,
expandable, expanded, etc,) are broad terms and include, but are
not limited to, spreading, swaging, drawing, radially expanding,
displacing, deforming, or other ways of displacing at least a
portion of a component.
The bushing 126 includes a first end 210, a second end 212 opposing
the first end 210, and a body 214 that extends between the first
and second ends 210, 212. The bushing 126 further includes an inner
surface 220 defining a passageway 221 and an outer surface 222. The
outer surface 222 includes an outer perimeter 224 that is sized to
closely fit (e.g., to provide a clearance fit with a minimal amount
of clearance, a slight clearance fit, or the like) within the
tubular body 136 of the retainer 122. The bushing 126 can thus be
easily inserted into the tubular body 136 and then expanded.
FIGS. 14 and 15 show an installation system 240 used to install the
nut plate assembly 100. To install the nut plate assembly 100, a
nose cap 242 of an installation tool 244 is placed against the
workpiece 110. An expansion mandrel 246 is pulled through the
tubular section 130 to expand both the bushing 126 and the tubular
body 136. The expansion mandrel 246 can be an elongate member
having at least one tapered portion or expanded portion used to
expand one or more components. Mandrels can have a one-piece or
multi-piece construction.
The installation tool 244 includes a main body 247 that is coupled
to a grip 248. The user can manually grasp the grip 248 to
comfortably hold and accurately position the installation system
240. The illustrated grip 248 is a pistol grip; however, other
types of grips can be utilized. The installation tool 244 can be
driven electrically, hydraulically, or pneumatically. In some
embodiments, the main body 247 houses a mechanical drive system
that drives the expansion mandrel 246, preferably along a
predetermined path (e.g., a line of action) in a proximal
direction, towards the installer, and/or distal direction, away
from the installer. A pair of fluid lines 251, 252 provides
pressurized fluid (e.g., pressurized gas, liquid, or combinations
thereof) to a drive system that actuates the expansion mandrel 246.
One of ordinary skill in the art can select the type of drive
system used to achieve the desired motion of the mandrel 246.
FIGS. 14-18 illustrate one process for installation of the nut
plate assembly 100. Generally, the tubular section 130 of the
retainer assembly 121 can be inserted into the opening 106. The nut
retaining section 140 is on the first side 138 of the workpiece 110
and the tubular section 130 extends away from the nut retaining
section 140 towards the second side 139 of the workpiece 110. After
positioning the retainer assembly 121 the mandrel 246 is moved
through the tubular section 130 from the first side 138 to the
second side 139 to expand the tubular section 130. Details of the
installation process are discussed below.
FIG. 16 shows the mandrel 246 ready to expand the assembled
retainer assembly 121. The retainer assembly 121 can be assembled
after or before the tubular body 136 is inserted into the workpiece
110. In some embodiments, the bushing 126 is positioned within the
tubular body 136 after the body 136 is inserted into the opening
106. In other embodiments, the bushing 126 is inserted into the
tubular body 136 and then the assembled bushing 126 and tubular
body 136 are inserted together into the opening 106.
FIG. 17 shows a mandrel tapered section 260 beginning to be pulled
through the tubular section 130 in the direction indicated by an
arrow 262. As the tapered section 260 progresses through the
tubular section 130, the tapered section 260 plastically increases
the respective dimensions (e.g., perimeters) of the expanded
bushing 126 and tubular body 136. For illustration purposes, the
radial expansion of the tubular section 130 is exaggerated. The
material of the bushing 126 is radially displaced into the material
of the tubular body 136 to form a desired fit between the outer
surface 222 of the bushing 126 and the inner surface 182 of the
tubular body 136. The material of the tubular body 136 in turn
radially displaces the inner surface 261 of the opening 206 to form
a desired fit between the outer surface 184 of the tubular body 136
and the inner surface 261. The tapered section 260 cold works the
workpiece material surrounding the retainer section 130 to provide
a fatigue benefit by creating compressive, residual stresses.
Referring to FIG. 18, the mandrel 246 has cleared the nut plate
assembly 100. The radially-expanded bushing 126 has a longitudinal
length L.sub.B that is substantially equal to, less than, or
greater than a longitudinal length L.sub.T (see FIG. 4) of the
tubular body passageway 180. The longitudinal length L.sub.B can be
substantially equal to or greater than the longitudinal length
L.sub.T to provide an interference fit throughout at least a
substantial portion of a longitudinal length L.sub.O of the opening
106. The longitudinal length L.sub.B can be measured along a
longitudinal axis 266 of the bushing 126. The longitudinal length
L.sub.T can be measured along a longitudinal axis 158 of the
tubular body 136.
The illustrated outer surface 184 of the tubular body 136 and the
outer surface 222 of the bushing 126 have been radially expanded to
provide substantially equal radial expansion throughout at least
most of the opening longitudinal length L.sub.O. In some
embodiments, the entire length L.sub.O of the opening 106 is
expanded. Induced compressive stresses in the workpiece material
272 surrounding or adjacent to the opening 106 may improve fatigue
performance of the installation. Additionally, the
radially-expanded nut retainer 122 of FIG. 18 can be
translationally and/or rotationally fixed with respect to the
workpiece 110 due to the compressive stresses developed during the
expansion process. The bushing 126 can be translationally and/or
rotationally fixed with respect to the nut retainer 122. Thus, each
component of the nut plate assembly 100 can be fixedly coupled
directly or indirectly to the workpiece 110.
The installed bushing 126 can help inhibit, limit, or substantially
eliminate relative movement between the workpiece 110 and the
retainer assembly 121, even if another component coupled to the
retainer assembly 121 via the nut member 120 is subjected to
various loading conditions, such as axial loads or torsional loads,
including static and cyclic loading. The bushing 126 can prop the
tubular body 136 against the workpiece 110.
The mandrel 246 can be reused or discarded. If reused, the mandrel
246 can be returned to a manufacturer to be reassembled into
another nut plate assembly 100. The manufacturer of the nut plate
assembly may or may not provide a refund or other incentive to
encourage the return of mandrels. In some embodiments, the mandrel
246 is disposable.
FIG. 19 shows a nut plate assembly 272 that includes a tubular
section 274 and a nut retaining section 276. Components of the nut
plate assembly 272 can be selected to provide different grip
lengths. Accordingly, the nut plate assembly 272 can be installed
into a wide range of workpieces, including thin sheets, thick
plates, and the like, and can be generally similar to the nut plate
assembly 100 discussed in connection with FIGS. 1-18, except as
further detailed below.
A longitudinal length L.sub.TS of the tubular section 274 can be
adjusted based on the thickness of a workpiece. Expandable members
of different lengths can be used to increase or decrease the
longitudinal length L.sub.TS of the tubular section 274. The
tubular section 274 of FIGS. 19 and 20 has an outer surface 278,
which is defined by a tubular body 280 of a nut retainer 282 and an
expandable member 284 in the form of a bushing. The length of the
exposed portion of the bushing 284 can be selected based on the
length L.sub.O of the opening 287 of the workpiece 289. Thus, the
illustrated nut retainer 282 can be installed into a wide range of
workpieces having different thicknesses.
Referring to FIGS. 21-23, the bushing 284 includes a first section
285 for placement in the tubular body 280 of the retainer 282 and a
second section 286 for physically contacting and expanding the
workpiece 289. The first section 285 and the second section 286
cooperate to define a bushing passageway 294. The bushing 284
includes a shoulder 288, illustrated as a stepped diameter, between
the first section 285 and the second section 286. As shown in FIG.
20, the shoulder 288 contacts an end 290 of the tubular body 280
when the first section 285 is positioned along a body passageway
292 of the tubular body 280.
The first section 285 has a longitudinal length that is
substantially equal to a length of the nut retainer tubular body
280. The second section 286 has a longitudinal length that is
substantially equal to a length of a section of the workpiece
opening 287 extending between the end 290 of the tubular body 280
and an outer face 291 of the workpiece 289. The illustrated second
section 286 of FIG. 20 protrudes from the end 290 and through the
opening 287 to the face 291.
Referring to FIG. 22, the first section 285 includes a first outer
perimeter 295, and the second section 286 includes a second outer
perimeter 296 that is greater than the first outer perimeter 295.
In some embodiments, the first outer perimeter 295 is generally
equal to or slightly less than an inner perimeter of the tubular
body 280. At least a portion of the first section 285 can also have
a transverse profile that is substantially geometrically congruent
to a transverse profile of at least a portion of the tubular body
280, before, and/or after the installation process. In some
embodiments, the first section 285 has a transverse profile that is
slightly smaller than the transverse profile of the tubular body
280 such that a slight interference fit is formed between the first
section 285 and the tubular body 280 before expansion. The first
section 285 and tubular body 280 can then be simultaneously
expanded.
At least a portion of the second section 286 can have a transverse
profile that is substantially geometrically congruent to a
transverse profile of at least a portion of the opening 287 before
and/or after the installation process. In some embodiments, the
second section 286 has a transverse profile that is slightly
smaller than the transverse profile of the opening 287 such that a
slight interference fit is formed between the second section 286
and the opening 287 before expansion. The second section 286 can
then be expanded to cause corresponding expansion of the opening
287.
To install the nut plate assembly 272 of FIG. 20, the tubular
section 274 is expanded to form a first interference fit between
the first section 285 of the bushing 284 and the tubular body 280
and a second interference fit between the second section 286 of the
bushing 284 and the workpiece 289. The tubular body 280 is expanded
a sufficient amount to form an interference fit with the workpiece
289. Thus, the tubular body 280 and the bushing 284 are fixed to
the workpiece 289 via interference fits.
In some embodiments, both the outer surface 283 of the tubular body
280 of FIG. 19 and the outer surface 281 of the second section 286
can be radially expanded to provide substantially equal radial
expansion throughout at least most of the longitudinal length of
the opening 287. In some embodiments, the entire longitudinal
length of the opening 287 is radially expanded to induce
compressive stresses in the material of the workpiece 289
physically contacting the tubular section 274.
FIG. 24 shows a mandrel assembly 300 for expanding the nut plate
assemblies disclosed herein. The mandrel assembly 300 includes a
mandrel 301 having an engagement portion 302, a tapered region 304,
a receiving surface 306, and a collar 308. The engagement portion
302 permits the mandrel 301 to be connected to an installation
tool. The tapered region 304 includes a minimum perimeter portion
310, a maximum perimeter portion 312, and a transition perimeter
portion 313 extending therebetween. The tapered region 304 is
positioned downstream, as indicated by the arrow 314, from the
engagement portion 302 and operates to radially expand components.
The illustrated maximum perimeter portion 312 of the mandrel 301 is
larger than the inner perimeter 188 of the retainer 122.
A uniform perimeter region 316 may be positioned adjacent to the
maximum perimeter portion 312 of the tapered region 304. The
uniform perimeter region 316 can be useful during the manufacturing
of the mandrel assembly 301. In some embodiments, the mandrel 301
may not have a uniform perimeter region in order to reduce the
axial length of the mandrel 301. The maximum perimeter portion 312,
for example, can extend from the receiving surface 306.
The receiving surface 306 is positioned near the tapered region 304
and includes an outer perimeter 317 sized to receive an expandable
member, such as the bushing 126 or bushing 284 described above. The
outer perimeter 317 can be sized to receive (e.g., loosely receive
with a clearance fit) the expandable member so as to minimize,
limit, or substantially prevent damage to the inner surface of the
member. For example, when the bushing 126 of FIG. 26 is positioned
along the receiving surface 306, the bushing 126 is axially fixed
with respect to the mandrel 301. The bushing 126 can be pulled
towards the retainer 122 as shown in FIG. 27.
The outer perimeter of the bushing 126 is sized to be equal to
(e.g., maximum tolerance conditions) or at least slightly smaller
than the inner perimeter 188 of the radially-expanded retainer 122.
This relative sizing allows the bushing 126 to be passed (e.g.,
pulled, pushed, or both) into the retainer 122 such that the
bushing 126 props open the tubular body 136. In some embodiments,
the bushing 126 can be inserted into the tubular body 136 without
damaging the bushing 126. The relative size of the radially
expanded tubular body 136 can also permit the bushing 126 to be
passed into the radially expanded tubular body 136 so that the
tubular body 136 can contract (e.g., collapse, constrict, and the
like) about the bushing 126. For example, the tubular body 136 can
elastically contract to form an interference fit with the bushing
126, which both supports and limits the radial contraction of the
tubular body 136.
Referring to FIG. 28A, a shoulder 318 can form the transition
between the maximum perimeter portion 312 or the uniform perimeter
region 316 and the receiving surface 306. The illustrated shoulder
318 is in the form of an annular step. Other shoulder
configurations are also possible.
FIGS. 28B-E show shoulders used to generate somewhat uniform
distributions of residual stresses in the tubular body 136 of the
retainer 122. The shoulder 318 of FIG. 28B defines an arcuate outer
surface 319 extending from the uniform perimeter region 316 to the
receiving surface 306. The tubular body 136 of the retainer 122 can
cam easily over the shoulder 318 and onto the bushing 126. FIG. 28C
shows a down-tapered shoulder 318. The rate of taper of the
shoulder 318 can be increased or decreased to decrease or increase
the distance between the bushing 126 and the uniform perimeter
region 316. The shape, size, and position of the shoulder 318 can
be selected based on the desired interaction between the mandrel
301 and the retainer 122. FIG. 28D shows the shoulder 318
comprising a plurality of steps from the uniform perimeter region
316 to the receiving surface 306. FIG. 28E shows the shoulder 318
connecting the maximum perimeter portion 312 to the receiving
surface 306.
The height of the shoulder 318 can be selected based on the
configuration of the bushing 126 and the installation process. FIG.
28A shows the shoulder 318 with a height H that is generally equal
to the wall thickness T of the bushing 126. In some embodiments,
the wall thickness T of the bushing 126 is less than the height H
of the shoulder 318 of the mandrel 301. In some embodiments, at
least a portion of the wall thickness T of the bushing 126 is
greater than or equal to the height H of the shoulder 318. These
relative sizes permit the bushing 126 to be slid into the
radially-expanded tubular body 136 during installation without
appreciably damaging these components.
Referring to FIGS. 28B-28E, the bushing 126 can include an
engagement portion 313 configured to engage another component. The
engagement portion 313 can be a layer (e.g., a coating or plating)
of a wear resistant material, lubricant (e.g., an anti-fretting
lubricant), or anti-fretting material that is applied to the
bushing 126. The engagement portion 313 can reduce friction, for
example friction between the bushing 126 and another component (not
shown) that may move relative to the bushing 126.
One type of engagement portion 313 may be a silver coating applied
for wear purposes that may include an amount of silver iodide to
enhance lubricity of the silver coating. Alternatively or
additionally, the portion 313 can be formed of a polymer, such as
synthetic resin lubricants like polytetrafluoroethylene (PTFE),
TEFLON.RTM., nylon, NEDOX.RTM. CR+, blends, mixtures, and
combinations thereof. These materials can be generally referred to
as "soft" because they are generally softer than the main bushing
material (e.g., steel). Thus, these relatively soft engagement
portions are generally more prone to being damaged during the
installation process.
Referring again to FIGS. 24 and 25, the collar 308 is positioned
downstream from the receiving surface 306 and engages the mandrel
301 to position the bushing 126 during the installation process.
The receiving surface 306 is interposed between the shoulder 318
and the collar 308. As shown in the embodiment of FIG. 25, the
collar 308 can serve as a stop to position the bushing 126 at least
proximate to the shoulder 318 of the mandrel 301.
The illustrated collar 308 includes internal threads that engage a
threaded region 320 of the mandrel 301. The collar 308 can be
rotated about the threaded region 320 to adjust the distance
between the shoulder 318 and the face 309 of the collar 308 for
contacting the bushing 126. The collar 308, once placed on the
mandrel 301, may be torqued down to provide at least a slight
compression force on the bushing 126 depending on the compressive
strength capacity of the bushing 126. In this manner, the collar
308 and shoulder 318 cooperate to limit or substantially prevent
axial movement of the bushing 126 along the mandrel 301.
The various embodiments described above can be combined to provide
further embodiments. All of the above U.S. patents, patent
applications and publications referred to in this specification, as
well as U.S. Pat. Nos. 3,566,662; 3,892,121; 4,187,708; 4,423,619;
4,425,780; 4,471,643; 4,524,600; 4,557,033; 4,809,420; 4,885,829;
4,934,170; 5,083,363; 5,096,349; 5,405,228; 5,245,743; 5,103,548;
5,127,254; 5,305,627; 5,341,559; 5,380,136; and 5,433,100; and U.S.
patent application Ser. Nos. 09/603,857; 10/726,809; 10/619,226;
10/633,294, and 11/653,196 are incorporated herein by reference.
Aspects can be modified, if necessary or desired, to employ
devices, features, elements (e.g., fasteners, bushings, mandrels,
and other types of expandable members), and concepts of the various
patents, applications, and publications to provide yet further
embodiments. For example, the nut plate assemblies disclosed herein
can be installed using the mandrels or other installation tools
disclosed in the incorporated patents and applications.
From the foregoing it will be appreciated that, although specific
embodiments of the invention have been described herein for
purposes of illustration, various modifications may be made without
deviating from the spirit and scope of the invention. Accordingly,
the invention is not limited except as by the appended claims.
* * * * *